Exercise: Power Electronics

Questions for: Power Electronics

The terminals of a power BJT are called
A:
emitter, base, collector
B:
emitter, base, drain
C:
source, base, drain
D:
source, base, collector
Answer: A

In a BJT terminals are emitter, base and collector irrespective of rating.

📖
📝
💬
👁️
A two winding transformer is feeding a single phase half wave rectifier circuit. The load is purely resistive. The rms value of transformer secondary current is Is and rms value of load current in Irms. Then
A:
Is = Irms irrespective of the value of firing angle
B:
Is = 0.5 Irms irrespective of the value of firing angle
C:
Is = Irms if firing angle is less than 30°
D:
Is = Irms if firing angle is more than 30°
Answer: A

.

📖
📝
💬
👁️
An electric heater is controlled by thyristors through on-off control. If a = 0.4, the heating is
A:
16% maximum
B:
40% of maximum
C:
60% of maximum
D:
84% of maximum
Answer: B

Vl = V a. Therefore Vl2 - V2 (a). Heating is proportional to a.

📖
📝
💬
👁️
In a single phase full wave regulator, the firing angles in the positive and negative half cycles are generally
A:
equal
B:
different
C:
equal or different
D:
different but sometimes equal
Answer: A

Firing angles are kept equal to get symmetrical output voltage.

📖
📝
💬
👁️

Assertion (A): If the duty cycle of chopper is low the current would not become discontinuous

Reason (R): If the time constant L/R of the load in chopper is low the current may become discontinuous.

A:
Both A and R are correct and R is correct explanation of A
B:
Both A and R correct but R is not correct explanation of A
C:
A is correct but R is wrong
D:
A is wrong but R is correct
Answer: C

If duty cycle is low, current may become discontinuous.

📖
📝
💬
👁️
Ad Slot (Above Pagination)
Quiz